Andres Limias Villa, 9, left, and Omar Limias Villa, 11, peer out their front gate after seeing Chicago police cars swarm outside their West Lawn home. The officers detained one person and were searching the street for a possible gun he had thrown.

Andres Limias Villa, 9, left, and Omar Limias Villa, 11, peer out their front gate after seeing Chicago police cars swarm outside their West Lawn home. The officers detained one person and were searching the street for a possible gun he had thrown. (Brian Cassella, Chicago Tribune)

Andres Limias Villa, 9, left, and Omar Limias Villa, 11, peer out their front gate after seeing Chicago police cars swarm outside their West Lawn home. The officers detained one person and were searching the street for a possible gun he had thrown.